Metallic coating and process of making same.



M. U. SGHOOP. METALLIC COATINGS AND PROCESS 0F MAKING SAME.

APPLICATION FILED APR.1,'191 0.

1,128,058. Patented Feb. 9, 1915.

2 SHEETSSHEET 1.

M. U. $011003. METALLIC COATINGS AND PROCESS OF MAKING SAME.

APPLICATION FILED APR. 1,1910.

1,128,058. Patented Feb. 9, 1915.

2 SHEETS-SHEET 2.

Mtg/Maw r In ven/for 1 UNITED STATES PATENT oFFroE.

MAX ULRICH SCHOOP, or HtiNGG, NEAR zumcn, swITzEnLANn, ASSIGNOR, BY irnsNE ASSIGNMENTS, To METALS COATING COMPANY or Amnmca; or nosToN, massacHUsnTTs, a CORPORATION or MASSACHUSETTS.

METALLIC COATING AND PROCESS OF MAKING Specification of Letters Patent.

To all whom it may concern Be it known that I, Max ULRICH Sonoor, a citizen of the Republic of Switzerland, residing at Hongg, near Zurich, Switzerland, have invented certain new and useful Improvements in Metallic Coatings and Processes of Making Same; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to homogeneous metal layers or coatings on articles of various kinds and the process of making same, which coatings may be extremely tenacious, or capable of being removed.

The fundamental idea of the invention consists in that the metal is applied to the surface to be treated, for example articles of metal, wood, paper, fabric and the like, in a finely divided molten or plastic condition, and to this end is sprayed, projected or blown onto the surface to be coated by means of a suitable agent capable of exerting the required pressure, or of atomizing the metal. This agent may be either high pressure steam, hot compressed air, or any other gas or vapor under suflicient pressure to atomize the metal in a suitable atomizer, whether heated or not. Instead of atomizing the metal, the liquid metal may be projected onto the surface to becoated in very fine or capillary streams, or a number of streams united toform a spray, there being used for the purpose one or more nozzles of suitable form through which the molten metal is forced. In some cases I have forced a continuous fine stream of metal from a nozzle and broken the continuity of the stream by rapidly vibrating the nozzle, or a stream of metal may be directed against an inclined plate and thus sprayed. The subdivision of the liquid metal. can also be accomplished in a mechanical way by a suitable centrifugal machine, and, finally, a

large number of metals may be projected and atomized in a molten state in an apparatus similar in structure to the atomizers used in medicine. The metal in this device is projected or forced from the bath in a fine continuous stream or thread, and then coming into contact with the issuing air or gas is immediately atomized. The pressure medium used for atomizing may be either neutral, in so far as the metal is concerned, or it may have a chemical action on the metal as it is atomized, which chemical action may be either oxidizing or reducing. It is immaterial how the liquid metal is atomized, or whether the apparatus used for the subdividing the metal as described is stationary or transportable, as the fundamental idea consists in producing coatings of any desired thickness by projecting liquid metal in a finely divided state onto a suitable article or base, said coatings being uniform, homogeneous and of good appearance. If it is important to obtain a coating en- .tirely free, or almost entirely free from oxid, andin case the subdivided or atomized metal has a tendency to oxidize, then it is necessary to use an inert gas as a pressure and atomizing medium. Such a result is", however, not always desired. On the other hand, under certain circumstances it may an unoxidized metallic coating in the manner set forth, and subsequently oxidizing the same in an oxidizing atmosphere in a closed chamber, or otherwise. By suitably selecting or dimensioning the atomizing apparatus, the atomized metal can be sub-divided so extremely fine that it resembles a cloud, so tha when the article to be coated is brough into the same there results a surface coating having a beautiful, smooth metallic luster. The metallic microscopic globules or drops of this metallic cloud, on account of their great speed, due to the liquid metal being under pressure, are pro jected with great force from the atomizing nozzle. These globules are flattened out and formed into very thin scales that lie adjacent to and overlap one another, so that they are welded together, which results in an intimately connected metallic sheet or coherent metallic body whose structure is very dense and tough.

This coating may be composed of a mixture of metals, by using a molten mixture which is atomized and projected onto the body or article to be coated. Fluxes may be used, and added to the metal in the melting Patented Feb. 9, 1915.

pot, and the flux may be such thatit is -va'- coating is, therefore, dependent upon the manner in which it is produced, and must be' varied according to the effect to be achieved on the article to be coated.

Coatings maybe made that may be subjected to any desired subsequent mechanical treatment, such as pressing, stamping, dressing, planing, etc., without damaging them or loosening them from their bases.

The melting point of the metal of the coating, the character and temperature oi the surface to'be'coated, the pressure used in atomizing and the thickness to be attained, as well as the distance of the nozzle from the object to be coated, will more or less influence the character of the coatings to be made as well as the manner in which the coatings are made. It is sometimes advisable to subject the objects to be coated to a certain cleaning action, for example, to clean them by a sand blast fromadhering dirt, oxid, or the like, or by'means of an acid orany other substance used for cleaning metal surfaces;

further, in many cases it is advantageous,

especially where metallic articles are to be coated or plated to meet varying demands of trade, to heat these articles before or during the coating operation, and thereby insure a coating that will strongly adhere to its base. 7

Nearly all metals are sufliciently fluid at suitable temperatures to produce fine subdivision in accordance with this invention, and no difiiculty is found in working with them. Some metals, however, present difficulties, such as zinc and aluminium, which can only be sub-divided or atomized by mixing them with fluxes or with other metals in small quantities. By this process it is possible to produce durable aluminium articles in a practical manner, or to coat metallic articles with aluminium, which has heretofore not been possible electrolytically.

It is obvious that alloys of metals may be used instead of substantially pure metals.

Thus far I have described the making of coatings which strongly adhere to their bases, but my invention, is not limited to such coatings.

I will now describe how I make removable metal coatings, for the reproduction of printing clichs, medals, &c. In order to produce, these removable coatings it is necessary or advisable to oil or grease the matrix or base, to coat it'with graphite; or

1,1aa,ose

treat it in any other well-known manner for the purpose of preventing the adhesion of the metallic coating; and 1n some cases it is desirable to keep the matrix heated during the application of the metallic coating, but

this may be dispensed with in the majority of cases where the coating to be applied is not extraordinarily thick. In order to make a comparatively thick coating, and thereby a coating readily separable from its base, the time, during which the surface from which the impression is to be taken is exposed to the atomized or finely divided ,1netal, is regulated in accordance with the thickness. of the reproduction to be obtained. For example, for the manufacture of printin clichs of about six millimeters thickness, It is generally sufficient to expose the negative mold .to the action of the atomiz ed metal for about tenseconds. After the metallic coating has been formed on the matrix as above'described, the matrix ma be dropped into cold water to quickly shrin it, and thereby readily release it from the article made.

In certain cases it is quite possible to make extremely thin metal sheets, that are readily removed from their bases, for example, for

the production of metallic foil; and in some instances it is advisable to have the matrix or base as smooth as possible, in order to more readily release the metal coating after it has been formed.

' Metallic sheets or foils which have been formed on polished or cut glass in the manner described, will adhere to these. only by the action ofatmospheric pressure, and remind one in their structure and general appearance of the photographic transfers made on polished glass, and have a very high luster.

By. my method it is possible to quickly and cheaply reproduce matrices and printing blocks of all kinds, medallions, and the like, which has heretofore been done by electrolytic methods. In ten hours, with the same negative matrix, from three hundred to four hundred reproductions can be made, which are as shar and fine in every detail, and as beautiful 1n their appearance as electrically plated reproductions. The metallic particles are thrown with great force, compared to their size, onto the ma trix or support, and are cemented or welded together into a compact metallic sheet forming a coherent metallic body. A further advantage of my new rocessconsists in that the electrolytic bath is entirely avoided, so

aluminium and other metals can be used,.

which cannot readily be done in an electrolytic bath. Further, a is readily possible to make seamless metallic tubes, or hollow vessels, and to this end a core of suitable material is placed in the metallic cloud and rotated, or the atomizer may be moved around the core or base to be covered; after which the core is either physically or chemically removed, by melting or burning it out, or by removing it by acids. The thickness of these removable metal coatings may be varied within comparatively wide limits, and the thickness obtained within a definite time will depend upon the gas pressure used for atomizing or subdividing the liquid metal, and upon the gas itself, whether oxidizing. reducing or neutral. The distance the object is held from the atomizing nozzle, as well as the size of the openings in said atomizing nozzle are also factors upon which the thickness depends. The density of the particles of coating is dependent upon the distance the article is held from the atomizing nozzle, as the shorter the distance the less time the atomized particles have to cool or set, or to become oxidized. -If the pressure medium used for atcmizing the fluid metal is neutral, then there is practically no difference whatever in the metallic coating formed and the general character of the metal. If the pressure medium is capable of oxidizing the metal, then the coating contains more 'or less oxid and is more or less porous, so that there will be a limitation to the thickness to which said coating can be made.

A peculiarity of the metallic cloud, or atomized metal, is that in general its temperature is very low, and the finer the atomization the lower the temperature, and of course the finer the atomization the greater will have to be the gas pressure used to produce it, so that materials may be used as matrices whose melting and ignition temperatures are very low, for example, such materials as hard paper and celluloid. It is also possible to hold the naked hand in the metallic cloud without injury, or without feeling any pain, which shows that the most delicate tissues can be reproduced. The temperature may be varied within wide limits as circumstances demand or permit. I have used the process in cases 'where the temperature of the metallic cloud was in the neighborhood of 60 Celsius, and also in cases where the temperature was increased to 200 Celsius and more.

Figures 1 and 1 taken together show by way of example one form of apparatus suitable for carrying out my invention, being partly in section and partly in elevation.

In the particular form of apparatus illustrated, a, a, are the steel flaskscontaining compressed gas, for example, air. These flasks are connected to a coil 0 contained in a suitable casing 0' provided with a gas burner d for heating the coil and the air therein which has become cold by reason of expansion. The metal 7 is contained in a preferably but not necessarily closed melting pot i providedwith a valve h controlling the outlet to the pipe m which termiuates in a downwardly directed nozzle g. The heating coil 0 has two branches, one In entering the pot '1' above the level of the metal 7 and the other I terminating adjacent the nozzle 9. The atomized metal is directed onto the object e to be coated, which is contained in a chamber 12.. Pressure gages b, b

are placed in the gas conduit.

l. The process of metallically plating or coating articles, which comprises finely and uniformly subdividing a molten metal maintained under pressure, and projecting it upon the surface to be coated with sufficient force to produce a uniform, non-porous welded coating.

The process of forming a coherent metallic body, which comprises finely subdividing a metal under the combined action of heat and pressure, and substantially at the same time projecting said subdivisions upon a surface with suflicient force to produce a non-porous, homogeneous body.

3. The process of forming a coherent metallic body, which comprises finely subdividing a metal under the combined action of heat and pressure, and substantially at the same time projecting said subdivisions upon a surface with sufficient force to produce a non-porous, homogeneous body, and controlling the pressure during projection.

4. The process of metallically plating or coating articles, which comprises finely and uniformly subdividing a molten metal by means of a gaseous pressure medium having a coloring action on the metal and projecting the finely divided metal by the same medium upon the surface to be coated with sufficient force to produce a nonporous welded coating.

5. The process of metallically plating or coating articles, which comprises finely and uniformly subdividing a molten metal under pressure, and projecting the finely divided molten metal onto the surface to be coated, by means of a gas capable of acting chemically on the metal.

6. The process of metallically plating or coating articles, which comprises atomizing a molten metal by means of a gas capable of oxidizing the metal to be atomized, and projecting the finely divided metal upon the surfaces to be coated.

7. The process of metallically plating or coating articles, which comprises providing the articles with a clean surface and projecting atomized liquid metal under pressure onto the articles.

8. The process of metallically plating or coating articles, which comprises cleaning the articles and projecting atomized liquid metal onto the article while hot with a force suflicient to flatten the particles of metal and thereby weld them into a uniform non-porous coating.

9. An article having a metallic coating, said coating comprising finely divided metallic particles of uniform size adjacent to and overlapping one another in a non-porous coating of uniform surface texture.

10. An article having a metallic coating, said coating comprising finely divided, more or less flattened metallic globules adjacent to and overlapping one another and welded together, presenting a uniform, non-porous surface readily burnished.

11. The process of metallically plating or tallic body, which comprises finely subdivid-- ing ametal 'underthe combined action of heat and pressure, and substantially at the same time projecting said sub-divisionsby a gaseous medium upon a'surface with sufficient force to produce a non-porous, homo-- geneous coating and controlling the pressure of said medium.

14. The process of forming a coherent metallic body, which consists in finely subdividing a metal under the combined action of heat and a gaseous pressure medium having a coloring action on the metal, and substantially at the same time projecting said subdivisions upon a surface with sufficient force to produce a non-porous, homogeneous body.

15.- The process of forming a coherent me-.

tallic body, which consists in finely sub-dividing a metal under the combined action .of heat and a gaseous pressure medium having a: coloring action on the metal, and sulostantially at the same time projecting said subdivisions upon a surface with suflicient force to produce a non-porous, homogeneous body, and controlling the pressure of said medium.

16. The recess of forming .a coherent metallic b0 y, which consistsv in finely subdividing a metal under'the combined action of heat and a gaseous pressure medium having a chemical action on the metal, and substantially. at the same time projecting said said subdivisions upon a surface with suflicient force to produce a non-porous, homo.- geneous body. H l I 17. The process of forming a coherent metallic body, which consists'in finely sub-dividing a metal under the combined action of heat and a gaseous pressure medium having a chemical action on the metal, and substantially at the same time projecting said subdivisions upon a surface with sufficient force to produce a non-porous, homogeneous body,

and controlling the pressure'of said medium,

18. The process of forming a coherent metallic body, which consists in finely subdividing a metal under the combined action of heat and a gaseous pressure medium capable of oxidizing the metal, and substantially at the same-time projecting said subdivisions upon a surface with sufiicient force to produce a partially oxidized, non-porous, homogeneous body. v

\ 19. The process of ,forming a coherent metallic body, which consists in finely subdividing a metal under the combined action of heat and a gaseous pressure medium capable'of oxidizing the metal, and substan tially at the same time projecting said subdivisions upon a surface with suflicient force to produce a partially oxidized, non-porous, homogeneous body, and controlling the pres sure of said medium.

In testimony that I claim the foregoing as my invention, I have signed my' name in presence of two subscribing witnesses.

MAX ULRICH SCHOOP.

l/Vitnesses VVILHELM REINHARD, CARL GUBLER. 

